Screw driver



June 6 1939.. c. s. SCHAFFER SCREW DRIVER Filed July 24, 1956 2 SheetS -Sheet 1 June 6, 1939 c. s. SCHAFFER SCREW DRIVER I Filed July 24. 1936 2 Sheets-Sheet 2 w\w\\ \\\\R\\\\\\\\\\\\\ 50 bit.

Patented 6, 1 939 UNITED STATES PATENT I orrrcs Charles i i g-L m.

'4 Claims.

This invention relates to an improvement in screw drivers and has as a principal object the provision of a screw driver which will itself hold a screw while the same is being inserted. j

' .A further object of the invention is-the provision of a screw holding screw driver which is positive in action and which may be operated with one hand, the mechanism being controlled by a. simple movement of the thumb or finger.

I Another important object of this invention is to provide a screw driver which may readily be used for rough work without danger of damage to the screw holding elements, which, as shown on the drawings and set out in this specification, 16 maybe withdrawn into the mechanism, when the screw driver is used in any manner other than as a screw holding tool.

A further object of this invention is to provide a screw driver as above set out which is of simple 0 and sturdy construction and free from a multiplicity of parts.

A further highly important object of this invention is to provide a screw driver of the screwholding type which is easy and economical to manufacture.

Other and further objects will be apparent from drawings and the detailed description in this specification.

On the drawings:

, 3o Fig. 1 is a view of the invention in elevation.

Fig. 2 is a view partially in elevation, the remainder in section, giving a principallycentral vertical sectional view of the internal mechanism.

Fig. 3 is a sectional view of the hollow mechanism-containing cylinder and the solid operating cylinder and operating button taken on the line 3-3 of Fig. 1, the operating button being in elevation.

Fig. 4 is a central vertical sectional view of the mechanism-containin cylinder.

Fig. 5 is a central vert cal sectional view of the wedge-shaped end bit or blade of the screw driver, showing the longitudinal center hole through the same. a

Fig. 6 is an elevational view of the internal mechanism of the screw driver showing the solid cylinder, operating button, or headed screw, coil spring and wire screw-kerf gripping rod shaft or Fig. 7 is a perspective view of the screw driver tip engaging a conventional screw head.

Fig. 8 is a diagram taken on the line 88 of Fig. 3, showing the point of the screw driver in its position relative to the kerf or slot in a screw head whenthe kerf-gripping rod is retracted or rotated parallel to the blade.

Fig. 9 is a diagram taken on the same line as Fig. 8, illustrating the action of the wedge-shaped end of.the-rod as it engages the side walls of the 5 slotin a conventional screw head.

Fig. 10 illustrates a modification of the inventlon for use with standard bit-retaining clamps or jaws such as are used on drills, braces and the like. 10

As shown on the drawings:

The numeral 1 I illustrates a handle such as is conventionally used on screw drivers and other hand operated tools. At its upper end the bandle ll carries the sleeve member E2, the rearmost 15 section of which'may extend substantially into the center of the handle or may extend therethrough or may be held by other mechanical means. As shown in Fig. 2, this sleeve is tapered at its upper end and centrally bored a portion oi. 5 its length to receive and retain the hollow mechanism-enclosing cylinder IS. a

Cylinder l3 extends into and is butt-welded or fastened by a transversely extending pin to the sleeve member l2 at its rearmost portion, as shown 'in Fig. 2. Enclosed within cylinder I3 is the spring-retained slidable and'partially rotatable solid cylinder member I5. At its lowermost end solid cylinder member I5 is reduced in size,

a shoulder extending around its entire circumfcrence, the reduced portion l5b extending substantially into the center space between the coils of spring ll.

A substantially L-shaped guide' slot 130. is cut through the side walls of cylinder I3, the shorter portion of said slot extending longitudinally of said cylinder and the longer part extending lat-- erally of the cylinder. Extending through the L-shaped slot is the mechanism operating button or headed screw it comprising a head !6a and a. threaded shank l6b which may be threadin hollow member [3. It is'also preferably spot welded or otherwise fastened, as indicated in Fig. 2, at its extreme end in the relative position hereinafter described, to the inner wall of said cyl- 5.

' inder member or may be attached, for example, to the rearward end of,tip"member M.

The tip member [4 is a metal cylinder. In preferred form it may be tapered out as shown on the drawings, but it may also be a cylinder 0! uniform thickness throughout. At its' rearward end it is offset and formed into a shoulder so that it may be inserted into and retained in the end of cylinder I3, forming a smooth union of these parts. A longitudinal hole Mb is chambered or bored the entire length of tip I4 to accommodate and rotatably and slidably retain the rod shaft or bit I8. At its extreme end, the tip member I4 is wedge-shaped, as is the usual construction in screw. drivers, forming an end I8a of rod I 8., End I8a is-wedge-shaped; being as wide in its most narrow direction as the extreme end of tip Ida, and being no wider in its widest portion than the diameter of hole Mb, to allowretraction of rod I8 into hole I ll).

As shown in Fig.8, in inoperative position the wedge-shaped end of said rod remains parallel to the wedge-shaped portion of the top of the screw driver blade. As shown in Fig. 9, in op' erative position this wedge-shaped end I8a is rotated so that the corners formed by the opposed surfaces engage and impinge upon the adjacent inner surfaces of a conventional screw slot. To assemble this tool, the rod shaft or bit I8 is inserted into and spot welded to cylinder member I5. The coiled spring I I is likewise spot welded to cylinder member I5, as shown in Fig. 6. .This assembly is then inserted into cylinder I3, the threaded hole I5a in cylinder member I5 being positioned beneath the cut-out L-shaped,v

slot In in said' cylinder. The operating button 5 is then inserted through the L-shaped slot and the shank I6b is then securely threaded into the hole I5a in cylinder member I5. The coil spring I! is then compressed in cylinder I3 and rotated so as to put tension on the now relatively fixedly retained cylinder member I5, creating a tendency in rod I8 to both project and rotate.

While in this position, the loose end of sprin I! is fastened, preferably by spot welding to the inner surface of cylinder I3 or to the rearward end of tip I4 so that the spring has a normal tendency to rotate the rod I8 in a counterclockwise direction, looking at the handle butt end. This assembly is then inserted into sleeve member I2 and tip member I4 is then slipped overthe rod I8 and placed in contact, as illustrated in Fig. 2, with the upper end of cylinder I3.

Cylinder I3 is then butt-welded to tip member I4, and fastened by means of a pin to sleeve I2. After the welding operations are completed, the handle II may be attached. However, in the modified structure shown in Fig. 10 it is obvious that no handle need be attached inasmuch as the rearmost end is designed to be inserted in a conventional drill chuck.

When the screw driver is used as a conventional tool the operating button I6 is positioned in the rearmost section of the substantially L- shaped slot I30, where it is retained by the tension of the rotated spring II, causing friction between the shank I61) and the edges of the L-,

shaped slot. While'thus held, the wedge-shaped end of rod I8 is substantially parallel to the extreme outer edge of the tip I la, although then retracted in hole Mb.

When used as a screw holding screw driver the rotate.

operating button I8 is slipped forward, the action of spri g I! forcing cylinder I5 and attached rod I8 to slide forward into the slot and tip Ila and and rotated position In most extended the wedge-shaped end I 8a of rod I8 is substantially pe pendicular to the contacting edge of tip 4a.

It is apparent from the foregoing description andattached drawings that I have invented a screw driver which has all the advantages herein set out and accomplishes these'objects by novel mechanical means.

I am aware that numerous detailsof the construction of my invention may be varied through a wide range without departing from the principles ofmy invention, and I therefore do not desire to limit my patent to the particular or preferred form illustrated.

I claim:

1. In a screw driver adapted to hold a screw while being inserted, the combination of an end, adapted to be gripped, a hollow cylinder'forming a casing and having a substantially L-shaped slot in the side thereof, the topmost portion of said slot extending rearwardly parallel to the axis of said hollow cylinder and forming a recess extending rearwardly, a manually operable lever extending through said slot and fastened to a plug in said cylinder and rotatable and retractable in said cylinder within the limits defined by said L-shaped slot, a coil spring in said cylinder fastened at one end to said plug forwardly thereof and at the other end to the internal surface of said cylinder imparting resilient movement to said plug, an end portionattached to said cylinder having a wedge-shaped bit forming a main bit adapted to contact \a screw kerf and having a longitudinal central bore therethrough and a secondary bit in said bore extending'longitudinally therein axially through said spring in said cylinder and fastened to said plug in said cylinder and rotatable and retractable therein in conjunction with the like movement 'of the spring controlled plug and the manually operable lever said secondary bit being coterminate with the end of said main bit in'most extended position and retracted therein when the manually operable lever is placed in the rearw ardmost portion of said L-shaped slot. a

2. A screw driver comprising'a handle, a sleeve connected thereto and extending therein, a tubular cylinder fastened to said sleeve and handle having a substantially L-shaped slot therein adaptedto allow an external manually operable lever to extend therethrough, the rearwardrnost portion of said L-shaped slot forming a recess parallel to the longitudinal axis of said tubular cylinder adapted to removably lock said lever in relatively retracted position, a solid cylinder in said. tubular cylinder fastened to said lever, a coil spring positioned longitudinally in said tubular cylinder forwardly of said solid cylinder and fastened rearwardly on'the frontmost portion of said solid cylinder and at its forward end to the internal wall of said cylinder creating a tension, a retractable bit extending longitudinally within the coils of said spring in said tubular cylinder and attached to said solid cylinder, and an end member having a bifurcated wedge-shaped tip and a longitudinal central bore, said retractable bit adapted to be rotated and retracted in said bore in cooperation with said solid cylinder and said lever attached thereto and in most extended screw and removably retain the same on said wedge-shaped tip. I

3. In an article of the described class the combination of a centrally longitudinally bifurcated truncated tip forming a main blade adapted to be inserted in the kerf oi a screw and having a longitudinal central bore therethrough, said tip rigidly attached rearwardly to a hollow barrel having a substantially L-shaped slot formed in the wall thereof, the said L-shaped slot extending rearwardly parallel to the longitudinal axis of said barrel at its rearwardmost part and in a plane at right angles to the longitudinal axis of said barrel at its end nearest thetip'of said blade, a movable spring retained cylindrical plug in said barrel, a lever attached to said plug and extending outwardly through said L-shaped slot and permitting movement of said plug within the limits of said slot, a secondary blade having a truncated tip rigidly attached to said plug and extending forwardly thereof centrally in said barrel and in the central longitudinal bore of said main blade and being coterminate with the tip of said main blade in most extended position and retracted in said main blade in most retracted position, a coil spring in said hollow barrel. mounted forwardly of said plug and extending longitudinally in said barrel adapted to create a tension on said plug in any position of said plug with respect to said L-shaped slot, and means adapted to permit gripping of the entire device.

4". In a screw driver the combination of a main blade having a bifurcated wedge-shaped tip and having a longitudinally extending central bore extending therethrough, a semi-rotatable and retractable secondary blade having a truncated tip mounted in said central bore in said main blade,

, wardly of said main blade,"said tubular cylinder being provided with a substantially L-shaped slot in the'wall thereof, the rearwardmost portion of saidv slot extending rearwardly of said tubular cylinder parallel to the longitudinal axis thereof forming a rearwardly extending recess, a coil spring extending longitudinally in said tubular cylinder, the rearwardmost end of said spring being rigidly attached to a semi-rotatable and relatively retractable cylindrical plug and the forwardmost end of said spring being attached to the inner wall of said tubular cylinder, a semirotatable and retractable cylindrical plug forming a rearward mounting for said secondary bit, an operating lever extending through the L- shaped slot in said tubular cylinder and rigidly attached to the cylindrical plug in said tubular cylinder adapted to permit spring retained and restricted movement of'said cylindrical plug and the secondary bit attached thereto within the space limited by the movement of said lever in said slot, said secondary bit being retracted from the bifurcated wedge-shaped tip of said main blade when said operating lever is in the rearwardmost portion of said L-shaped slotand coterfninate with the tip of said main blade and semi-rotatable substantially crosswise with respect thereto when in most extended position, the wedge-shaped tip of said secondary blade thereby gripping the edges of the kerf of a screw and releasably retaining said screw on the tip of said main blade, and an end extending rearwardly of said hollow tubular cylinder forming a means for holding the device above described.

CHARLES S. SCHAFFER. 

